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Friday, July 10, 2009

Cheerleading safety efforts have led to modest reductions in the number of serious injuries in recent years, according to a new report about college and high school sports and cheerleading mishaps.

But cheerleading caused more serious and deadly injuries by far than other female sports during the study period.

Researchers have long known how dangerous cheerleading is, but records were poorly kept until recently. An update to the record-keeping system last year found that between 1982 and 2007, there were 103 fatal, disabling or serious injuries recorded among female high school athletes, with the vast majority (67) occurring in cheerleading. The next most dangerous sports: gymnastics (nine such injuries) and track (seven).

Today, the National Center for Catastrophic Sports Injury Research at the University of North Carolina at Chapel Hill released its 26th annual report on the topic. The latest figures are from the 2007-2008 academic year for college and high school sports, male and female. The report defines catastrophic injuries as any severe or fatal injury incurred during participation in the sport.

The new numbers are for the 26-year period from the fall of 1982 through the spring of 2008:

There were 1,116 direct catastrophic injuries in high school (905) and college sports (211).

Cheerleading accounted for 65.2 percent of high school and 70.5 percent of college catastrophic injuries among all female sports.

The number of cheerleading injuries fell slightly in the 2007-08 academic year.

"Progress has been slow, but there has been an increased emphasis on cheerleading safety," said the study's author Frederick O. Mueller. "Continued data collection on all types of cheerleading injuries will hopefully show that these safety measures are working to reduce injuries."

Thursday, July 9, 2009

Fireworks for the 4th of July are all about light, color and sound. But inside, there are some bizarre ingredients, from aluminum to Vaseline and even the stuff of rat poison.

An ancient mix of black powder, essentially gunpowder little changed from its invention in China a millennia ago, gets each rocket in the air by creating pressure in gas trapped in a tube, or mortar.

Two fuses are lit at once: one to ignite the black powder, and another that burns slower, creating a well-timed explosion high in the sky.

The shells of commercial fireworks contain a powdery concoction of chemicals that produce the bangs and the whistles, as well as the pretty effects. Tubes, hollow spheres, and paper wrappings work as barriers to compartmentalize the effects. More complicated shells are divided into even more sections to control the timing of secondary explosions.

Big booms and whistles come from flash powder. Once used for flashes in photography, it is a combination of fuel-like metal and a chemical that feeds oxygen to fire up the fuel. Different combinations of metals and oxides produce a whole array of sounds.

While ancient Greeks and Romans used bismuth in their beauty care products and coins, chemists add bismuth trioxide to the flash powder to get that crackling sound, dubbed "dragon eggs." Ear-splitting whistles take four ingredients, including a food preservative and Vaseline.

The variety of color in a fireworks show depends on the mix of metals.

In recent years, chemists have worked to develop more environmentally friendly fireworks, in part because one ingredient, perchlorate, was found in higher than normal concentrations in a lake where fireworks were shot off, and the chemical is known to cause thyroid problems in humans.

Meanwhile, to light up a red, white, and blue flag, chemists can lay out the emblem's design on wax paper. The pattern you see up in the air, whether it's a smiley face or a bow tie, mirrors the arrangement of the metals in the shell.

Because the flag, or any other pattern, shoots out from the shell as a two-dimensional image, people watching the show from different angles can't always tell what they're looking at. To make sure everyone has a good view, pyrotechnists tend to send duplicates into the sky at the same time.

You can see fireworks before you hear them because light travels faster than sound.

Sunday, July 5, 2009

Researchers have built an inchworm-like robot so small you need a microscope just to see it. In fact about 200 hundred of them could line up and do the conga across a plain M&M. The tiny bot measures about 60 micrometers wide (about the width of a human hair) by 250 micrometers long, making it the smallest untethered, controllable microrobot ever. "It's tens of times smaller in length, and thousands of times smaller in mass than previous untethered microrobots that are controllable," said designer Bruce Donald of Dartmouth University. "When we say ‘controllable,' it means it's like a car; you can steer it anywhere on a flat surface, and drive it wherever you want to go. It doesn't drive on wheels, but crawls like a silicon inchworm, making tens of thousands of 10-nanometer steps every second. It turns by putting a silicon 'foot' out and pivoting like a motorcyclist skidding around a tight turn."

Because it makes use of this innovative bending movement and is untethered, it can move freely across a surface without the wires or rails that restricted the mobility of previously developed microrobots. The caterpillar strategy also helped the researchers avoid a common problem in microrobotics. "Machines this small tend to stick to everything they touch, the way sand sticks to your feet after a day at the beach," said Craig McGray of the National Institute of Standards and Technology. "So we built these microrobots without any wheels or hinged joints, which must slide smoothly on their bearings. Instead, these robots move by bending their bodies like caterpillars. At very small scales, this machine is surprisingly fast." To get around, the robot makes use of two independent microactuators – the robot's "muscles." One is for forward motion and the other for turning. It doesn't have pre-programmed directions. Instead, it reacts to electric changes in the grid of electrodes it moves on. This grid also supplies the microrobot with the power needed to make these movements.

This microrobot and similar versions that could be developed might eventually ensure information security, inspect and make repairs to integrated circuits, explore hazardous environments, or even manipulate human cells or tissues.

Alan Izhar-Bodner, an Israeli inventor, has developed a way for divers to breathe underwater without cumbersome oxygen tanks. His apparatus makes use of the air that is dissolved in water, just like fish do.

The system uses the "Henry Law" which states that the amount of gas that can be dissolved in a liquid is proportional to the pressure on the liquid. Raise the pressure - more gas can be dissolved in the liquid. Decrease the pressure - gas dissolved in the liquid releases the gas. This is exactly what happens when you open a can of soda; carbon dioxide gas is dissolved in the liquid and is under pressure in the can. Open the can, releasing the pressure, and the gas fizzes out.

Bodner's system apparently uses a centrifuge to lower pressure in part of a small amount of seawater taken into the system; dissolved gas is extracted. The patent abstract reads: A self-contained open-circuit breathing apparatus for use within a body of water naturally containing dissolved air. The apparatus is adapted to provide breathable air. The apparatus comprises an inlet means for extracting a quantity of water from the body of water. It further comprises a separator for separating the dissolved air from the quantity of water, thereby obtaining the breathable air. The apparatus further comprises a first outlet means for expelling the separated water back into the body of water, and a second outlet means for removing the breathable air and supplying it for breathing. The air is supplied so as to enable it to be expelled back into the body of water after it has been breathed.

Human beings have been thinking about how to breathe underwater since they started swimming. This long-held desire plays an important part in one of the first great science fiction novels, Jules Verne's 20,000 Leagues Under the Sea. It consists of a reservoir of thick iron plates, in which I store the air under a pressure of fifty atmospheres. This reservoir is fixed on the back by means of braces, like a soldier's knapsack.

More recently, I distinctly remember an episode of the sixties sf series Voyage to the Bottom of the Sea in which a scientist decides that the best way to breathe underwater is to give himself gills. Alas, once equipped with gills, and fully acclimated to life in the sea, Dr. Jenkins and his associate lie in wait outside the submarine Seaview, converting every diver who emerges from the ship into mermen.

And, of course, everyone remembers the scene in which intrepid Jedi Obi-Wan Kenobi and Qui-Gon Jin don pencil-sized breathing masks to explore the swamp lakes of Naboo in The Phantom Menace. This trick is used again in the most recent Star Wars movie.

Wednesday, July 1, 2009

Lupon Vocational High School, Lupon, Davao Oriental offers PC HS to students who specialize in ICT enabled curriculum. This school year is its first implementation of the said curriculum. There are 40 students presently enrolled in the course.

Computer Hardware Servicing provides an excellent introduction to the IT industry and in-depth exposure to personal computers, hardware, and operating systems in accordance to local industry requirements and standards. Students learn the functionality of various hardware and software and best practices in maintenance and safety issues. This course prepares students for entry-level as computer technician positions within various environment.This is aligned with TESDA National Certification Level II.